Scanning LF, MF [medium format], 35mm and ...

My Father is 85 years old and obviously retired. Years ago he had a photo studio and part of that time I worked full time plus for him other periods I worked part time or if and when needed.

Today, he gave me a box of glass negatives he was given to see if any were worth keeping, scanning, and possibly printing.

He also has informed me that years ago he started going through his negatives [4X5", 2¼" AKA 6cm X?], 35mm and possibly some very old (by his standards) 127 film]; however, he became ill and has had several strokes along with some other problems and never finished.

He would like me to go through all and see if I can get them to whomever was in them, those which  are of any historical importance to the proper organizations, and scans or prints of his personal photos to family members,  etc.

To see what I could do with a flat bed scanner I tried a few; without a great deal of luck. Most are too dense for the flatbed to scan.

So the question is is there way to handle this I have thought of renting a film scanner on occasions I might have sufficient time to work on the project,  or purchasing a used scanner, I also thought of making a light box and photographing them with a 24mp camera.

The idea of having them done by some one else has occurred; however, there might be many thousands to do over several years and that scares me [the price that is].

Ideas are welcome [but please don't laugh too hard simply be glad you are not the one who was requested to do this].

--
Ray RJNedimyer